Jun 132018

Today is the birthday (1773) of Thomas Young FRS, an English polymath, called “The Last Man Who Knew Everything” by Andrew Robinson in his biography, subtitled, Thomas Young, the Anonymous Polymath Who Proved Newton Wrong, Explained How We See, Cured the Sick, and Deciphered the Rosetta Stone, Among Other Feats of Genius. Young made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony, and Egyptology. He was mentioned favorably by, among others, William Herschel, Hermann von Helmholtz, James Clerk Maxwell, and Albert Einstein. It’s also Maxwell’s birthday today, by the way: http://www.bookofdaystales.com/james-clerk-maxwell/

Young was born in Milverton in Somerset, the eldest of 10 children in a Quaker family. By the age of 14 Young had learned Greek and Latin and was acquainted with French, Italian, Hebrew, German, Aramaic, Syriac, Samaritan, Arabic, Persian, Turkish and Amharic. He began to study medicine in London at St Bartholomew’s Hospital in 1792, moved to the University of Edinburgh Medical School in 1794, and a year later went to the University of Göttingen in Lower Saxony where he obtained the degree of doctor of medicine in 1796. In 1797 he entered Emmanuel College, Cambridge. In the same year he inherited the estate of his grand-uncle, Richard Brocklesby, which made him financially independent, and in 1799 he established himself as a physician at 48 Welbeck Street, London (now recorded with a blue plaque). Young published many of his first academic articles anonymously to protect his reputation as a physician.

In 1801, Young was appointed professor of natural philosophy (mainly physics) at the Royal Institution. In two years, he delivered 91 lectures. In 1802, he was appointed foreign secretary of the Royal Society, of which he had been elected a fellow in 1794. He resigned his professorship in 1803, fearing that its duties would interfere with his medical practice. His lectures were published in 1807 in the Course of Lectures on Natural Philosophy and contain a number of anticipations of later theories. In 1811, Young became physician to St George’s Hospital, and in 1814 he served on a committee appointed to consider the dangers involved in the general introduction of gas for lighting into London. In 1816 he was secretary of a commission charged with ascertaining the precise length of the seconds pendulum (the length of a pendulum whose period is exactly 2 seconds), and in 1818 he became secretary to the Board of Longitude and superintendent of the HM Nautical Almanac Office.

Young was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1822. A few years before his death he became interested in life insurance, and in 1827 he was chosen one of the eight foreign associates of the French Academy of Sciences. In 1828, he was elected a foreign member of the Royal Swedish Academy of Sciences. He died in London on 10th May 1829, and was buried in the cemetery of St. Giles Church in Farnborough, Kent, England. Westminster Abbey houses a white marble tablet in memory of Young bearing an extended epitaph by Hudson Gurney:

Sacred to the memory of Thomas Young, M.D., Fellow and Foreign Secretary of the Royal Society Member of the National Institute of France; a man alike eminent in almost every department of human learning. Patient of unintermitted labour, endowed with the faculty of intuitive perception, who, bringing an equal mastery to the most abstruse investigations of letters and of science, first established the undulatory theory of light, and first penetrated the obscurity which had veiled for ages the hieroglyphs of Egypt. Endeared to his friends by his domestic virtues, honoured by the World for his unrivalled acquirements, he died in the hopes of the Resurrection of the just. — Born at Milverton, in Somersetshire, 13 June 1773. Died in Park Square, London, 10 May 1829, in the 56th year of his age.

Young was highly regarded by his friends and colleagues. He was said never to impose his knowledge, but if asked was able to answer even the most difficult scientific question with ease. Although very learned he had a reputation for sometimes having difficulty in communicating his knowledge. It was said by one of his contemporaries that, “His words were not those in familiar use, and the arrangement of his ideas seldom the same as those he conversed with. He was therefore worse calculated than any man I ever knew for the communication of knowledge.” Young is quite well known by scholars in different fields but they usually know him only for his work in their specialties, not as a polymath.

I’ll just list briefly the areas where he made significant contributions – with a small synopsis.

Wave theory of light

In Young’s own judgment, of his many achievements the most important was to establish the wave theory of light. To do so, he had to overcome the view, expressed in the highly esteemed Isaac Newton’s Opticks, that light is a particle. Nevertheless, in the early-19th century Young put forth a number of theoretical reasons supporting the wave theory of light, and he developed two enduring demonstrations to support this viewpoint. With the ripple tank he demonstrated the idea of interference in the context of water waves. With his interference experiment (the now-classic double-slit experiment), he demonstrated interference in the context of light as a wave.

After publishing a paper on interference, he published a paper entitled “Experiments and Calculations Relative to Physical Optics” in 1804. Young describes an experiment in which he placed a narrow card (approximately 1/30th  inch) in a beam of light from a single opening in a window and observed the fringes of color in the shadow and to the sides of the card. He observed that placing another card before or after the narrow strip so as to prevent light from the beam from striking one of its edges caused the fringes to disappear. This supported the contention that light is composed of waves. Young performed and analyzed a number of experiments, including interference of light from reflection off nearby pairs of micrometer grooves, from reflection off thin films of soap and oil, and from Newton’s rings. He also performed two important diffraction experiments using fibers and long narrow strips. In his Course of Lectures on Natural Philosophy and the Mechanical Arts (1807) he gives Grimaldi credit for first observing the fringes in the shadow of an object placed in a beam of light. Within ten years, much of Young’s work was reproduced and then extended by others.

Young’s modulus

Engineers all know Young’s modulus, which describes the elasticity of materials beyond the limits of Hook’s Law. Hook’s Law describes the direct, proportional correlation between the load on a spring, and the extension of the spring “provided the load is not too great.” The proviso is there because if the load is “too great” all bets are off. Young’s modulus takes care of that. Young described his findings in his Course of Lectures on Natural Philosophy and the Mechanical Arts. However, the first use of the concept of Young’s modulus in experiments was by Giordano Riccati in 1782, predating Young by 25 years. Furthermore, the idea can be traced to a paper by Leonhard Euler published in 1727, 80 years before Young’s 1807 paper on the subject. Nonetheless, Young’s application was the one generally adopted by engineers. Young’s Modulus allowed, for the first time, prediction of the strain in a component subject to a known stress (and vice versa). Prior to Young’s contribution, engineers were required to apply Hooke’s F = kx relationship to identify the deformation (x) of a body subject to a known load (F), where the constant (k) is a function of both the geometry and material under consideration. Finding k required physical testing for any new component, as the F = kx relationship is a function of both geometry and material. Young’s Modulus depends only on the material, not its geometry, thus allowing a revolution in engineering strategies.

Vision and color theory

Young has sometimes been called the founder of physiological optics. In 1793 he explained the mode in which the eye accommodates itself to vision at different distances as depending on change of the curvature of the crystalline lens; in 1801 he was the first to describe astigmatism; and in his lectures he presented the hypothesis, afterwards developed by Hermann von Helmholtz, (the Young–Helmholtz theory), that color perception depends on the presence in the retina of three kinds of nerve fibers. This foreshadowed the modern understanding of color vision, in particular the finding that the eye does indeed have three colour receptors which are sensitive to different wavelength ranges.

Young–Laplace equation

In 1804, Young developed the theory of capillary action based on the principle of surface tension. He also observed the constancy of the angle of contact of a liquid surface with a solid, and showed how to deduce the phenomenon of capillary action from these two principles. In 1805, Pierre-Simon Laplace, the French philosopher, discovered the significance of meniscus radii with respect to capillary action. In 1830, Carl Friedrich Gauss, the German mathematician, unified the work of these two scientists to derive the Young–Laplace equation, the formula that describes the capillary pressure difference sustained across the interface between two static fluids. Young’s equation describes the contact angle of a liquid drop on a plane solid surface as a function of the surface free energy, the interfacial free energy and the surface tension of the liquid. Young’s equation was developed further some 60 years later by Dupré to account for thermodynamic effects, and this is known as the Young–Dupré equation.


In physiology Young made an important contribution to haemodynamics in the Croonian lecture for 1808 on the “Functions of the Heart and Arteries,” where he derived a formula for the wave speed of the pulse and his medical writings included An Introduction to Medical Literature, including a System of Practical Nosology (1813) and A Practical and Historical Treatise on Consumptive Diseases (1815). Young devised a rule of thumb for determining a child’s drug dosage. Young’s Rule states that the child dosage is equal to the adult dosage multiplied by the child’s age in years, divided by the sum of 12 plus the child’s age.


In an appendix to his Göttingen dissertation (1796; “De corporis hvmani viribvs conservatricibvs. Dissertatio.”) there are four pages added proposing a universal phonetic alphabet (so as ‘not to leave these pages blank’ –  Ne vacuae starent hae paginae, libuit e praelectione ante disputationem habenda tabellam literarum vniuersalem raptim describere”). It includes 16 “pure” vowel symbols, nasal vowels, various consonants, and examples of these, drawn primarily from French and English. In his Encyclopædia Britannica article “Languages”, Young compared the grammar and vocabulary of 400 languages. In a separate work in 1813, he introduced the term “Indo-European” languages, 165 years after the Dutch linguist Marcus Zuerius van Boxhorn proposed the grouping to which this term refers in 1647.

Egyptian hieroglyphs

Young made significant contributions in the decipherment of Egyptian hieroglyphs. He started his Egyptology work rather late, in 1813, when the work was already in progress among other researchers. He began by using an Egyptian demotic alphabet of 29 letters built up by Johan David Åkerblad in 1802 (14 turned out to be incorrect). Åkerblad was correct in stressing the importance of the demotic text in trying to read the inscriptions, but he wrongly believed that demotic was entirely alphabetic. By 1814 Young had completely translated the “enchorial” text of the Rosetta Stone (using a list with 86 demotic words), and then studied the hieroglyphic alphabet but initially failed to recognize that the demotic and hieroglyphic texts were paraphrases and not simple translations. There was considerable rivalry between Young and Jean-François Champollion while both were working on hieroglyphic decipherment. At first they briefly cooperated in their work, but later, from around 1815, a chill arose between them. For many years they kept details of their work away from each other. Some of Young’s conclusions appeared in the famous article “Egypt” he wrote for the 1818 edition of the Encyclopædia Britannica. When Champollion finally published a translation of the hieroglyphs and the key to the grammatical system in 1822, Young (and many others) praised his work. Nevertheless, a year later Young published an Account of the Recent Discoveries in Hieroglyphic Literature and Egyptian Antiquities, to have his own work recognized as the basis for Champollion’s system. Young had correctly found the sound value of six hieroglyphic signs, but had not deduced the grammar of the language. Young, himself, acknowledged that he was somewhat at a disadvantage because Champollion’s knowledge of the relevant languages, such as Coptic, was much greater. Several scholars have suggested that Young’s true contribution to Egyptology was his decipherment of the demotic script. He made the first major advances in this area. He also correctly identified demotic as being composed of both ideographic and phonetic signs.


Young developed two systems of tuning a piano so that it was well tempered (Wohltemperiert), that is, was tuned so as to be able to modulate between all major and minor scales without sounding obviously out of tune in any of them. Discussions of temperaments get really technical really quickly. Young’s first temperament was designed to sound best in the keys that were the commonest, and his second was a kind of inversion of the first. Unless you know the difference between BƄ and A#, and the differences that their major and minor thirds make in chords, this will not make any sense to you. It is a problem in the physics of acoustics, essentially.

Historians and critics vary enormously in their assessment of Young. Without question he was well versed in all the fields above – and more – and was able to expound on them critically (if not always clearly). How original his contributions were to the various fields, is the subject of ongoing debate. The idea than he was the last man to know everything, is obvious (and intentional) hyperbole. But it also highlights the fact that at the beginning of the 19th century it was still possible to gain expert knowledge in widely diverse fields. Furthermore, Young not only knew a lot of stuff, he was able to make contributions to diverse fields. Whether or not he was always entirely original is beside the point as far as I am concerned. We’re talking about a man who made contributions – recognized as significant by experts – in half a dozen specialties, that most of us do not even understand, let alone are capable of mastering.

As I have done quite a number of times with birthdays recently, I’ll celebrate Young with a recipe from his home region, Somerset. Somerset is well known for apples, cider, and dairying, and this recipe for Somerset chicken, which is traditional, combines all three.

Somerset Chicken


6 boneless chicken breasts, skin on
salt and freshly ground black pepper
75 gm/2½ oz butter
3 tbsp olive oil
2 onions, peeled and sliced
4 tbsp plain flour
2 tbsp wholegrain mustard
2 dessert apples, peeled, cored and sliced
110 gm/4 oz button mushrooms, sliced
250 ml/9 fl oz chicken stock
300 ml/10½ fl oz cider
1 tbsp finely chopped fresh sage
250 ml/9 fl oz double cream
300 gm/10½ oz cheddar cheese, grated


Preheat the oven to 200˚C/400˚F.

Season the chicken breasts with salt and freshly ground black pepper.


Heat a large skillet until smoking, then add half of the butter and oil. Fry the chicken breasts in batches, skin-side down first, for 5 minutes on each side, making sure they are golden-brown all over.  Transfer the chicken breasts to a baking dish and keep warm.

Return the skillet to the heat and add the remaining butter and oil. Add the onions and cook for 4-5 minutes, or until softened but without taking on color. Stir in the flour and the mustard and cook for a further 1-2 minutes. Add the apples and mushrooms and cook for a further minute, then pour the chicken stock over ingredients.

Bring the skillet to the boil, add the cider and return to the boil. Cook for 1-2 minutes, then lower the heat, add the sage and stir in the cream. Simmer for a further 5-6 minutes, then season with salt and freshly ground black pepper to taste.

Pour the sauce over the chicken in the baking pan.

Preheat the broiler to high.

Sprinkle the cheddar cheese over the chicken and place under the broiler for 4-5 minutes, or until the cheese is melted, golden-brown and bubbling.

Serve with baked or boiled new potatoes.